Advice wanted: Broken Kowa 824M Fluorite lens (3 Viewers)

[benjsham]

Hello all,

My brother experienced a tragic tripod malfunction the other day. When the dust settled, his Kowa 824M came up with a shattered front element. In the objective lens doublet, the front lens was fine but the internal lens was shattered. I believe this is the fluorite lens. Kowa USA has quoted a ridiculous charge of $830 for the fluorite element (due to this being the last 82mm fluorite lens they have in the USA) and a $85 installment charge. He acquired the scope and 32x eyepiece last year for less than $800 used! They say that they may be able to go ahead with a plain glass element for a lower charge. Two questions:

1) is there a cheaper way to acquire a 82mm fluorite lens element? Perhaps buying a heavily used or broken Kowa 823/824 for $400-500, pilfering the fluorite lens and having a local optics shop do the replacement?

2) would a plain glass front lens element be a noticeable drop in optical quality at 32x? It must add some degree of CA but at 32x this may not be terribly noticeable.

Any other ideas would be very appreciated.

Ben

 

[jring]

Hi,

sorry to hear that... indeed, the back element of the doublet is the fluorite one in all Kowa scopes with a fluorite element and most others too. The only exception I remember are the Takahashi FS series of astro scopes.

At 32x, a plain glass doublet will be fine unless your brother has 20/10 vision. I am not sure though if a back element from a plain glass doublet will work with the front element from a fluorite one,,, but Kowa service should know and will hopefully deliver back a usable scope...

Trying to find a donor 823/4 body might take considerable time and luck.

Joachim